Parking garages rarely merit much architectural discussion. Most of today's designs are no-frills stacks of open floors, laid out to accommodate as many cars as possible. With their shadowy interiors on full display, the naked concrete structures have the melancholy look of buildings that were never finished.

Yet, parking garages did not start out as a purely functional architectural form. For evidence, please see the exuberant, art deco garage that stretches for a full block on Chestnut between 11th and 12th Streets. Completed in 1940, its three public facades are fully clothed in limestone panels and richly detailed with ribbon windows, chrome fins, glass block, and glossy tilework. The ground floor is lined with welcoming retail space. Because it looks like a regular building, many people assume it is one, even though it houses 700 cars.

The Chestnut Street garage's good looks have a lot to do with its history. The project was proposed in 1921 by the Chestnut Street Association, an early merchants' group dedicated to promoting the street as a prime shopping destination. Although committed to providing convenient parking, the association felt it was crucial that the large structure shouldn't overwhelm the street's intimate pedestrian scale or interrupt its retail flow. It took more than a decade to pull off the project because the Great Depression put a halt to most construction.

Designed by Ballinger & Co., the garage not only maintains the street's retail atmosphere, it also succeeds in fusing style and functionality into a seamless whole. By 1939, when design work began, the art deco style had grown more subdued, and it produced an offshoot known as streamline moderne. With its thin, ribbon windows, the garage has the long, horizontal lines of a cruise ship. The architects contrasted those windows with diamond-patterned vertical sections and rounded door frames.

In the building's low-slung form, many will detect a resemblance to the suburban department stores that appeared a decade later. In fact, the original ground-floor tenant was the Snellenburg department store, which created a passage through the garage to its main Market Street outpost. It was succeeded by Mandel's, another big retailer. Today, a variety of shops, and a PGW office, occupy the ground floor, anchored by Airs Appliance, which maintains an art deco marquee.

The building is owned by National Real Estate Development, which is constructing the mixed-use East Market complex on the site of the original Snellenburg store. The developers haven't decided what to do with the garage. Ideally, they will cherish it as a stylish, early example of mixed-use development that put the pedestrian and the retail experience first.